This invention relates generally to automotive vehicles, and more particularly, to electrically-powered automotive vehicles.
Electrically-powered automotive vehicles have long been known as viable alternatives to conventional gasoline-powered vehicles, especially in urban areas, where noise pollution and air pollution problems are acute. An electrically-powered vehicle of basic design, having an electric motor powered by a battery, has not provided completely satisfactory performance, however, because the battery must be recharged at frequent intervals, thereby limiting the range of the vehicle.
Improvements over this basic design are disclosed in U.S. Pat. No. 3,690,397, issued to L. W. Parker and entitled "Electric Automobile," and in references cited therein. The improvements suggested by Parker and others all utilize the same underlying concept, that the battery is carried on a separate wheeled trailer towed by the primary vehicle. When these towed battery units become discharged, they can be exchanged for charged battery units at special automotive service centers, where the units are maintained in a charged and properly serviced condition. Although this concept is useful in some situations, it fails to overcome the drawback that the battery units must be recharged or replaced at frequent intervals and additionally, suffers from the drawback that the vehicle can be operated only along routes where the special service centers are located.
Additional improvements to the basic electric vehicle design briefly described above are disclosed in U.S. Pat. No. 3,497,027, issued to A. F. Wild and entitled "Electric Automobile," and include a vehicle having an electric motor and removable power units or pods. In one of the embodiments disclosed in this patent, the vehicle carries two power pods, one having a battery, and the other having a gasoline engine and electrical generator. The battery power pod is ordinarily used when driving in urban areas, where limited range is not a particular problem and where air pollution and noise restrictions may exist, while the gasoline engine power pod is normally used elsewhere. Additionally, the gasoline engine power pod can be used to recharge the battery power pod.
The dual power pod concept disclosed in the Wild patent, although satisfactory in some situations, suffers from the drawback that special lifting equipment would be required for removal of the gasoline engine power pod. For this reason, the gasoline engine power pod would ordinarily be carried by the vehicle at all times, even on short trips through urban areas where the pod would not be used, thereby imposing an unecessary load on the vehicle and causing a wasteful consumption of battery power. This dual power pod concept suffers from the additional drawback that the gasoline engine power pod, when in use, is operated at variable speed, and hence at less than maximum efficiency, and at more than minimum levels of harmful exhaust pollutants.
It will be appreciated from the foregoing that there is still a need for an electrically-powered vehicle having an electric motor powered by both a battery unit and a gasoline engine/generator unit, that can travel substantial distances without the need for battery recharging, and that can be operated in such a manner so as to maximize fuel efficiency and minimize exhaust pollutant levels. The present invention fulfills this need.